The proposed studies will examine the impact of parental support on adolescents' negative affect-motivated substance use during the transition to high school. Specifically, this research aims to examine 1) the nature and quality of a particular and relevant aspect of parental support (i.e., parental reactions to adolescents' distress) during adolescents' transition to high school, and 2) the impact of parental reactions to adolescents' distress on adolescents' use of substances to cope with their experience of stress and negative affect during the high school transition. Taken together, these studies will address limitations of the literature on family process and adolescent substance use in that the proposed studies focus on parent-adolescent interactional processes particularly relevant to adolescents' use of substances to cope. Advanced methodological (i.e., Experience Sampling Method, parent-adolescent observational data collection) and statistical analytic techniques (i.e., HLM) will facilitate a more sophisticated examination of the proposed aims.